You don’t need a wine buzz to “appreciate” “The Napa Boys,” a vulgar, lowbrow and clumsily unfunny send of up “Sideways” and lots of pop culture of similar vintage. But it probably helps.

There have been good reviews of this double-shot of diarrhea. Not many sober ones. Me? I could not be more disappointed if it had been about anarchic 40ish auto parts clerks on a bender in Motor City.

The novelty of it is its exercise in world-building, creating a sequel to a movie that neither needs nor could withstand one. We’re dropped in, mid-fame, on the careers of the (way-too-old) sons of the characters Paul Giamatti and Thomas Haden Church played for Andrew Payne back in 2004. The “Juniors” have become famous comic book creators and wine lovers, with podcasts obsessively devoted to their hijinks and a hint of mystery about whether their “graphic novel” adventures are fiction or “We LIVE the story” real.

Long in the tooth Miles Jr. (Armin Weitzman) is still mourning his late wife and unnamed (No room on the tombstone?) “little girl.” Jack Jr. (Nick Corirossi) has his Toyota FJ wrapped as a “Wine Wagon” for, we assume, tours of wine country. And he’s grabbing Miles Jr. “to get you laid” up Solvang way.

The first big “joke” of the movie — after that tombstone side-splitter — is the vanity plate on that Toyota — “IH8MRLT.” If you bust a gut over that, have I got a film festival “midnight movie” for you.

Sarah Ramos plays The Napa Boys’ “biggest fan,” an “investigative podcaster” who’s decided to follow them as they reunite with their other mates and recruit “Stiffler’s Brother” (Jamar Malachi Neighbors) to join their ranks for a quest supposedly plotted by the unseen, all-knowing and mystical “Sommelier,” whose emerald set tastevin will be their guide.

Their “grapes before gals” ethos may go out the window with Puck around. Not sure how that ever played into “get you laid,” in either “Sideways” or this abortive stepchild.

They roll up on gay vintner “Boy” Mitch (Mike Mitchell) as he’s stomping grapes in a grape barrel, with one and all sampling his raw grape juice with Dr. Scholl’s undertones and pronouncing it grand.

Mitch’s Winery is to compete in The Great Grape Festival’s wine-judging competition, which Jack Jr.’s sudden bout of intestinal distress sabotages via a drawn-out, butt-naked bowel movement over the submitted competition barrel. And that low point in the movie might win the Boys’ vintner nemesis, the racist/homophobic (but effeminaate) Squirm (Paul Rust) of Squirm Vineyards another blue ribbon.

What one hesitates long and hard before labeling “story beats” follow “Sideways” about as much as they mimic “The Lord of the Rings.” “Random” is the rule of the day as the picture could not set out to get more things wrong and be a bigger bungle.

Makeout music for the two waitresses Jack and Miles Juniors pick up (Vanessa Chester and Chloe Cherry) involves putting on an LP by The Chipmunks. Riffs on :American Pie,” “Fergully: The Last Rainforest” and the oeuvre of Kevin Smith, who makes an AARP-ready cameo in the third act with his other half, Jason Mewes, play like blind men groping for a laugh in the dark.

The picture is artlessly shot and edited as well, with Corirrosi and Weitzman scripting and Corirossi directing. Scene after scene, starting with the opening “Ah, Napa Valley in the vine-barren browns of winter” shot, begins with dead space — pointless, paceless footage — and is cut well after the shot or the scene’s payoff.

Perhaps that, like the very basic blunders about wine and the protocols of wine-judging, was intentional. Smith goes all “Ratatouille,” daring anybody to criticize the movie because “We’re all just trying,” or CYA platititudes to that effect. He looks a little embarrassed. With cause.

Because somebody had family or whatever connections to get this flailing, winded lower-than-low comedy out of film festival midnight showings, where it belonged, and into distribution. More’s the pity.

Rating: unrated, sexual and scatalogical humor, profanity

Cast: Armin Weitzman, Nick Corirossi, Sarah Ramos, Jamar Malachi Neighbors, Chloe Cherry, Mike Mitchell, Vanessa Chester, David Wain, Raul Rust and Ray Wise, with Jason Mewes and Kevin Smith.

Credits: Directed by Nick Corirossi, scripted by Nick
Corirossi and Armin Weitzman. A Magnolia release.

Running time: 1:32